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inflight

Add callbacks to requests in flight to avoid async duplication

USAGE

var inflight =require('inflight')
// some request that does some stufffunctionreq(key, callback) {
// key is any random string. like a url or filename or whatever.//// will return either a falsey value, indicating that the// request for this key is already in flight, or a new callback// which when called will call all callbacks passed to inflightk// with the same key
callback =inflight(key, callback)
// If we got a falsey value back, then there's already a req goingif (!callback) return// this is where you'd fetch the url or whatever// callback is also once()-ified, so it can safely be assigned// to multiple events etc. First call wins.setTimeout(function() {
callback(null, key)
}, 100)
}
// only assigns a single setTimeout// when it dings, all cbs get calledreq('foo', cb1)
req('foo', cb2)
req('foo', cb3)
req('foo', cb4)